Trends in Incidence of Abdominal Aortic Aneurysm Rupture, Repair, and Mortality in Nova Scotia

Abstract

The purpose of this study was to examine sex-based trends in incidence of elective abdominal aortic aneurysm (AAA), ruptured AAA, ruptured AAA repair, and AAA-related mortality. A retrospective analysis of patients presenting with AAA from 2005 to 2015 was conducted. Rates of elective AAA repair, ruptured AAA, ruptured AAA repair, and mortality were obtained from linking provincial administrative data using medical services insurance billing number. The age-adjusted incidence of elective AAA repair, overall rate of ruptured AAA, ruptured AAA repair, and AAA-related mortality was calculated for each sex based on Canadian census estimates, adjusted to the Canadian standard population. Weighted linear regression was performed to analyze trends in incidence over time. One thousand nine hundred eighty-six elective AAA repairs were identified, of which 1,098 were repaired open and 898 underwent endovascular abdominal aneurysm repair (EVAR). Five hundred and seventy ruptured AAAs were identified, of which 295 (52%) were repaired: 259 open and 36 EVAR. The proportion of ruptured AAA that was repaired did not change over time (P=0.54). The proportion repairs performed using EVAR increased significantly in both elective (P<0.001) and rupture repairs (P<0.001). During the study period, 662 patients died of AAA-associated mortality. The average incidence of elective AAA repair in men was 29.3 (95% confidence interval (CI): 27.8 to 30.8) per 100,000 and decreased over time (P=0.04), whereas the average incidence in women was 9.2 [8.3 to 10.0] and stable (P=0.07). The incidence of open elective AAA repair was 10.5 [9.9-11.1] with a decreasing trend over time (P<0.001) and EVAR was 9.0 (8.5-9.6) with an increasing trend over time (P<0.001). A decreasing trend of overall ruptured AAA (5.4 [5.0-5.9], P<0.001), ruptured AAA repair (2.9 [2.5-3.2], P=0.02), and of AAA-related mortality (6.2 [5.8-6.8], P<0.001) was found, with consistent trends in both sexes. The incidence of open ruptured AAA repair decreased over time (P=0.001) whereas the incidence of ruptured EVAR remained stable (P=0.23). The incidence of elective AAA repair is decreasing in males but not females, whereas the incidence of rupture has decreased in both sexes. This has translated into reduced incidence of AAA-related mortality. Increased adoption of EVAR for ruptured AAA should continue these trends.